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No. 28,718. PATENTED JUNE 12, 1860.4

E. M. LBWs. SLIDE VALVE.

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UNITED STATES PATENT OFFICE.

ENOS M. LEWIS, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO EIMSELF AND GEORGE WILLIAMS, OF SAME PLACE.

SLIDE-VALVE FOR STEAM-ENGINES.

Specification of Letters Patent No. 28,718, dated June 12, 1860.

To all lwhom it may concern:

Be it known that I, ENos M. Lnws, of the city of Philadelphia and State of Pennsylvania, have invented a new and useful Improvement in Slide-Valves for Steam-Engines; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawing and to the letters of reference marked thereon.

My invention consists in the combination of a slidevalve of the form of a hollow box, on outer boxl or casing with rollers, certain springs or their equivalents and a follower forming a stuffing box between the said outer casing and the valve, the whole being constructed and arranged substantially in the manner described hereafter, so that the pres-V sure of the steam may be removed from the valve and sustained by the rollers of the outer box thereby preventing the undue friction common to ordinary slide valves.

In order toenable others skilled in the art to make and use my invention I will now proceed to describe its construction and operation.

On reference to the accompanying drawing which forms a part of this specification, Figure 1, is an end view of my improved slide valve. Fig. 9 a side view, partly in section, on the line l, 2, Fig. 1. F ig. 3, a section of Fig. l. Fig. l, a section of Fig. 2, and Fig. 5, a ground plan.

Similar letters refer to similar parts throughout the several views.

The valve consists of a hollow box B bearing with its face on the valve seat represented by the line A.

The face of the valveis in every respect similar to that of an ordinary slide valve, the sides and ends, however, are planed perfectly true and at right angles to the face, so as to lit snugly but slide freely in the follower C which is adapted to a recess in the outer box or casing D and forms a stung box containing packing to prevent the steam from gaining access to the space between the top of the valve B and top of the casing D, the follower being connected to this casing by the set screws L a..

At each of the four corners of theouter casing D is a roller d the journals of which turn in lugs e c secured to or forming a part of the said casing, the peripheries of the rollers bearing on a lateral continuation of the valve seat Between the top of the casing and the top of the valve intervenes any convenient number of spiral or other springs F, F, which serve to maintain the said valve in contact with its seat,

It will be observed that the whole pressure of the steam exerted on the outer casing is resisted solely by the rollers (Z, d, the only pressure on the valve being such as is exerted by the springs f f or other equivalent Y appliances; it will be evident therefore that although the valve is maintained in close steam tight contact with the seat it is free from the excessive friction of ordinary slide valves which detracts so materially from the power of the engine.

I am aware that slide valves have been heretofore furnished with rollers for antifrictional purposes. I therefore do not claim broadly such a device, but

I claim as my invention and desire to secure by Letters Patent- The combination of the valve B, outer box or casing D, its rollers (l, CZ, the springs f f or their equivalents, and the follower C. the whole being constructed and arranged substantially as and for the purpose herein set forth.

In testimony whereof, I have signed my name to this specification, in t-he presence of two subscribing witnesses.

ENOS M. LEWIS.

Witnesses:

HENRY I-IowsoN, CHARLES D. FREEMAN. 

